The invention is directed to oil-modified polyester products, as well as oil-free polyester products. The invention is directed to the novel process for the production of these products. Moreover, the invention is directed to novel compositions realized by using the oil-modified polyesters, or oil-free polyesters, to produce varnishes.
It is generally known that maleic anhydride or trimellitic anhydride can be used to form polyesters which can become water-soluble. The maleic anhydride or trimellitic anhydride act to provide carboxylic sites for aqueous solubilization. The polyesters produced from these reactants are rendered water-soluble by the aid of an amine, a metal oxide, hydroxide or carbonate.
It has been found that a variety of polycarboxylic acids, or their respective anhydrides, can be employed to produce polyester products to effect solubility, in the same manner as maleic anhydride or trimellitic anhydride effect solubility in polyester products.
The polyester products of the invention are water-dispersible polyesters which may be used as protective coatings systems for industrial and architectural applications.
The invention provides new polyesters which can be formed from compositions containing considerable amounts of monocarboxylic acids; alternatively, the polyesters of the invention can be formed from components with the exclusion of monocarboxylic acids altogether. Some of these new polyesters are commonly known as "oil-free" polyesters.
The polyesters of the invention may be used in improved coating systems for a variety of metal and non-metal substrates and are characterized by superior heat and chemical resistance properties.
Aqueous coatings, formed from a polyester of the invention, have improved flow, wetting, non-foaming characteristics, as well as improved film continuity upon application to particular substrates.